1. Field of the Invention
The present invention relates to a keyboard, and more particularly, to a keyboard with a two-dimensional actuator for generating direction signals which can be used to move a cursor shown on a screen to a target position.
2. Description of the Prior Art
When editing a text file by using a window-based text editing program, such as Microsoft Word for Windows, the cursor which shows where a text character will be inserted on a screen, can be moved to a target position on the screen by using four direction keys: up, down, left, and right keys of a numerical keypad which is usually installed on the right hand side of a keyboard. Besides, a user can also scroll the screen by using the page-up and page-down keys of the numerical keypad to move the cursor to a front page or a rear page, or using the home and end keys to move the cursor to the beginning or ending position of a text line.
Three drawbacks are found about using the keys on the numerical keypad to move the cursor shown on the screen. First, the numerical keypad usually can be set to a numerical-key mode or to a direction-key mode by using a number lock key. A user must make sure that the numerical keypad is set to the direction-key mode before using the direction keys of the numerical keypad to move the cursor. Second, in order to continually enter text characters into a computer, the left and right hands of a user are required to be put over two predetermined positions of a keyboard. But when using the direction keys of a numerical keypad is required to move the cursor, the user must move his or her right hand to the numerical keypad which will cause an interruption over the text input work. Third, if the user is not familiar with each key's position of the numerical keypad, he or she must continuously watch the numerical keypad in order to find the required key before pressing it. Such drawbacks will usually cause inconvenience to the user when using the numerical keypad.
Some keyboards contain a pointing device such as a point sticker, track ball, touch pad, etc., installed approximately at a central position of the keyboard which permits a user to move a pointer shown on a screen by using a thumb or an index finger without moving his or her right hand. However, the signals generated by such a pointing device and the way to use such pointing device are quite different from the four direction keys or the four control keys (page-up, page-down, home and end keys) of the numerical keypad.
The signals generated by such a pointing device are inputted into a computer through a serial port instead of a keyboard port. A separate line is required for connecting the pointing device to the computer for transmitting the signals generated by the pointing device. Besides, the signals generated by such a traditional pointing device are used to move a pointer displayed on a screen instead of moving a cursor or scrolling a screen, like the four direction keys or the four control keys. The signals generated by the four direction keys or the four control keys of the numerical keypad are used by traditional text editing programs to move the cursor or scroll the screen directly. If the pointing device is used to move the cursor to a target position on a screen, the user has to move the pointer to a target position first and then click a left button of the pointing device which will activate the text editing program to relocate the cursor to the target position. When scrolling a screen, the user has to move the pointer to work with a scrolling bar to scroll the screen. Such differences make the pointing device installed at the central position of a keyboard not so easy to reform the functions of the four direction keys and the four control keys of the traditional numerical keypad.